Switchboard



A ril 14, 1942. w. M. SCOTT, JR

SWITCHBOARD Original Filed Aug. 27, 1938 3 Sheets-Sheet l ATTORNEY A ril 14, 1942. w. M. SCOTT, JR 2,279,841

I SWITCHBOARD Original Filed Aug. 27, 1958 3 Sheets-Sheet 2 INVENTOR %%A-M;4

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ATTORNEY A ril 14, 1942. I w. M. scioTT, JR 2,279,341

\ Y SWI'IGHBOARD Original Filed Aug. 2'7, 1938 3 Sheets-Sheet 3 INVENTOR )MAA M BY I M ATTORNEY Patented Apr. 14, 1942 SWITCHBOARD William M. Scott, Jr., Bryn Mawr, Pa., assignor, by mesne assignments, to I-T-E Circuit Breaker Company of Pennsylvania Original application August 27, 1938, Serial No.

1940, Serial No. 331,697

11 Claims.

My invention relates to switchboards for use with removable or truck-type circuit-breakers, and more particularly relates to disconnect arrangements providing for disengageable connec tion between the contacts of circuit-breakers and conductors or busses of switchboards.

In accordance with my invention, the stationary disconnect contacts of the switchboard, engaged by the complementary movable contacts of the circuit-breaker unit when in service position, 1:;

are directly mounted upon or supported .by the conductors or bu'sses of the switchboard; preferably, upon each of the bus conductors is mounted a support for a plurality of disconnect contact elements having limited relative movements to ii accommodate misalignment or irregularity of the complementary disconnect contact structure of the circuit-breaker.

Further in accordance with my invention, each of the bus conductors is covered with insulation except'where exposedfor'support of a disconnect contact structure, and where so exposed is within an insulated housing which also encloses the disconnect contact structure for that bus conductor; more particularly, a wall of I the switchboard is provided with slots or openings, in alignment with the disconnect contacts in their respective housings, through which are introduced and withdrawn into and from service position the disconnect contacts of the circuit-breaker unit.

Further in accordance with my invention, the switchboard and the circuit-breaker unit having overlapping wings or wall elements which prevent access to the disconnect contacts on the circuit-breaker unit until after the unit has been so far withdrawn from its service position that its disconnect contacts have moved out of the housings enclosing the disconnect contacts on the bus conductors.

My invention further resides in the features of combination, construction and arrangement hereinafter described.

This application is a division of my co-pending application Serial No. 227,089 filed August 27, 1938 now Patent No. 2,258,150.

For an understanding of my invention, reference is to be had to the accompanying drawings in which:

Fig. 1 is a front perspective view of a switchboard with a plurality of truck-type circuit breakers in service position;

Fig. 2 is a perspective view of the rear of the switchboard of Fig. 1 with some of its panels removed;

Fig. 3 is a perspective of part of the switchr;- riers.

Divided and this application April 26,

board of Fig. 1 with the truck units completely withdrawn and not shown;

Fig. 4 is a side view in section of one of the truck units of Fig. 1 and of its associated switchboard unit;

Fig. 5 is a perspective view on enlarged scale and with parts broken away of a disconnect arrangement shown in Fig. 4;

Figs. 6 and '7 are plan views in section illustrative of the relative positions of the truck and switchboard units when their disconnect contacts are engaged, Fig. 6, and disengaged, Fig. '7;

Fig. 8 is a rear view in perspective of the truck unit of Fig. 4.

Referring to Fig. 1, the switchboard SE is a rectangular metal-clad structure containing bus bars, cable connections, and one or more truck or withdrawal type circuit breakers 131-36. The stationary structure S, Figs. 2 and .3, of the switchboard comprises units Ell-85, corresponding in number with the circuit breakers, suitably mounted in alignment with each other.

The ends E, E of the switchboard are suitably reinforced steel panels attached to the end units S1, S6 and are substantially wider than the side panels of the units. Each of the units Sl-S6 consists of three compartments vertically aligned, individually covered with removable steel panels, and separated or sealed by horizontal steel bar- Since all units are, or may be'similar in construction, only one of them need. be described. Referring to Fig. 4, the uppermost'compartments l and la, of a unit S, exemplary of any of units S|-S5, are sealed from the next lower compartment 2 by the horizontal steel barrier 3; the upper wall 4 of the compartments I, la is a steel plate forming the top of the unit; the rear wall of the compartment 1 is the removable steel cover plate 5 and the sides of the compartment 1 are formed by side plates 6 extending from top to bottom of the unit. The steel partition 1 isolates the two compartments 1 and la from each other.

The upper compartments I, la contain auxiliary apparatus such as potential transformers PT, relays, and wiring from controland' signal contacts 8 which aresuitably mounted on the under side of that portion ofthe bottom of compartment or duct la which projects beyond the front wall of compartment 2. Other auxiliary apparatus as meters M, control switches and the like, may be mounted upon the'rear face (Fig. 4) of panel 5 for observation or operation from the rear of the switchboard.

Within the compartment 2 are supported the three bus conductors 9, 9a, 922 each wrapped in phenolic insulation, molded and cured and clamped in the impregnated maple blocks l0, lfla (Fig. 2) to withstand short-circuit stresses. To each tubular bus is directly attached a support H for disconnect contacts l2 whose purpose and construction are hereinafter described. Each of the disconnect contact assemblies for a bus conductor is enclosed in its individual housing l3 of insulating material. The rear wall of compartment 2 comprises the removable metal panel I4 and the front wall thereof comp-rises the upper part of the panel l5, of insulating material and in which there are three staggered slots I6 for permitting contacts ll extending from the rear of the circuit-breaker unit B to pass through the panel into the similarly staggered disconnect housings l3. Thus, when the unit B is withdrawn, it is impossible for an attendant accidentally to touch any uninsulated parts at high potential.

The bottom compartment [8 of the unit S, whose rear face is closed by the removable steel panel l9, contains cab-1e disconnect contacts, suitably encased in insulating housings 23, current transformers CT, and the outgoing cable connections therefrom. The housings are supported, as by insulators 2! from the cross brace 22, in alignment to receive the contacts 23 which pass through slots 24 in the lower part of panel I5 from the rear of the breaker unit B. The duct 25 along the front face of compartment l8 may be used to encase the wires from the transformers CT to a protective relay or electromagnet hereinafter identified. Access to the interior of duct 25 may be had by removal of the steel panel 25a.

Extending from the front of each unit (S I--S6) are the rails 26 for guiding the wheels 2'! of its associated circuit breaker unit (BlB6), a pair of lugs 28 whose purpose will hereinafter be described, and a dust shield member 29 for the auxiliary contacts 8. The rails 26 extend upwardly from the steel base 311 from which also extends the tripping cam 3! whose purpose will hereinafter appear.

The steel base 30, comprising plates and structural members, extends the length of the switchboard and forms a foundation to which the units are secured.

Reverting to the arrangement providing for disengageable connection of the bus conductors with disconnect contacts I! of the circuit-breaker unit B, the support H for the bus disconnect contacts I2 comprises two members Ha, Hb (Fig. 5) of metal which are clamped by bolts 32 directly to the bus conductor 9. From the front of member Hb extend the brackets 33 for supporting the pins 34, 35 upon which the upper and lower contacts 12 are respectively pivotally mounted. The upper and lower contacts l2 of each of the several groups shown in Fig. 5 are biased toward each other by a spring 36 which encircles a bar 31 through which loosely extend two yoke members.

The upper equalizing yoke 38 presses downwardly on the upper face of two adjacent upper contacts 12; a similar yoke (not shown) bears against the under faces of the corresponding pair of lower contacts l2. The pin 39 passes loosely through forward ends of all of the upper contacts l2 and similarly pin 40 passes loosely through the forward ends of all of the lower contacts l2. This contact construction, more fully described in United States Letters Patent #2,029,028 to Kneass et al., insures equal distribution of the contact pressure between contacts l2 and I! notwithstanding their appreciable misalignment.

The housing l3 which is assembled about the bus disconnect structure after the latter has been clamped to the bus conductor comprises two separable parts held together as by screws 4 l. Across the open front end of the housing extend two pivotally mounted shutters 42 of insulating material biased toward engagement with each other by springs 43. The gap between the forward edges of the shutters is in alignment with the corresponding slot l6, Fig. 4, in the panel l5. When the circuit-breaker unit B is pushed into position, each of the disconnect contacts l1 enters its corresponding slot 16, separates a pair of shutters 42, and slides between the upper and lower disconnect contacts l2. When the unit B is completely withdrawn, the shutters 42, 42 within each housing 13 close the corresponding panel slot l6 and preclude accidental contacts with the disconnect contacts l2.

As more apparent from Fig. 2, the bus conductors and live parts connected thereto are completely insulated and effectively isolated from each other. The bus conductors, as previously stated, are encased in insulation except within the insulating housings l3, and each disconnect contact assembly is within its individual housing l3 of insulation. When panel I4 is opened, there is, therefore, no possibility of accidental contact with any of the live parts within compartment 2. Moreover, as shown in Figs. 6 and '7, the sides 6, 6 of the unit S so far overlap the sides of the circuit-breaker unit B that it is not possible for an attendant to touch the contacts ll until after the unit B has been so far withdrawn from the switchboard that contacts H are out of engagement with the live disconnect contacts l2.

Each of the truck units Bl- B3, exemplified by unit B, Figs. 4 and 8, is a substantially rectangular structure formed by angle iron and sheet steel suitably joined as by welding. The door 44 which permits access to the circuit-breaker mechanism hereinafter described is provided near the top with a louvered opening 45 to permit escape of gases incident to circuit interruption and allow circulation of air for cooling. In the particular construction shown in Figs. 4 and 8, the top of the truck structure is closed by a sheet metal wall 46.

The circuit breaker and its operating mechanism is removable as a unit from the rear of the truck structure after it has been withdrawn from the switchboard. When the unit is in position, its wall 4'5 serves as the lower part of the rear wall of the upper or circuit-breaker compartment of the truck; the upper part of the rear wall of the truck compartment is an integral part of the truck structure.

The circuit breaker shown herein is a threepole breaker but since the constructions of all three poles are similar, only one is described. Referring to Fig. 4, the upper main contact assembly comprises a stud 66 which passes through the sleeves 67, 68 of insulating material. By tightening nut 70 on stud 66, the two sleeves El, 68 are forced tightly against opposite sides of the vertical wall 41 of frame 5|. Similarly, the lower main contact assembly I! is mounted upon a stud 12 which passes through sleeves l3, 14 of insulating material. By tightening nut 16, the sleeves l3, 14 are clamped to opposite sides of the rear vertical wall of the frame 5|.

The disconnect contacts ll, 23 are held to the studs L66, 12.by.the,nuts 11,18, respectively. The upper end .ofeach of the disconnect contacts I1 iszbraced by an insulator 119, Fig. 8, to resist bending .during insertion and withdrawal ,of the circuit-breaker unit B from the switchboard.

other. The insulator'85mechanically connected to the frame member 86 of assembly 1| and to the base plate 48.0f the unit frame 5| stiffens or supports the assembly 1| againstforces or shocks incident to the opening and closing movements of theparts of the circuit breaker.

The upper. main contact assembly, Fig. 4, comprises the main contact member. 81, the auxiliary contactmember flfi, the arcing. horn 89, the arcing tip-90, and theblowout coil .9I. The auxiliary contact;88 isbiased ,by a spring and connected by pigtail to the. main contact. A pair of links on oppositesides of contacts 81, 88 support and guide the latter during its movement.

The arcing horn 89 is mechanically connected to the main contact 81 by bolts which pass through sleeves of. insulating material and clamp the front and rear ends. of the horn against the platcs of insulating material.

One end of the blowout coil 9| wound upon core I92 is held in electrical connection with main contact 81 and the other terminal of the coil is held in electrical connection with the.

arcing horn structure. Electrical connection of the horn 89 with contact 81 except through the blowout coil is precluded by sleeves and plates of insulation. The co l is wound from heavy flat wire or ribbon covered withinsulation resistant to the effects of high temperatures.

The lower .main contact assembly 1|, Fig. 4, comprises the stationary frame member 89 within which is pivotally mounted the movable frame member I83 connected by pigtail (not shown) to the stationary frame member andto the bridging contact member I95 loosely pivotally mounted in the movable frame member I83. To the upper end of movable frame member I83 is attached the arcing contact II5 which, when the circuit breaker is closed, (Fig. 4), engages both the auxiliary or shunt contact 88 and the movable arcing horn tip 90.

All of the operating mechanism for the circuit breaker is supported from the under face of the horizontal wall 48 of the frame 5| and the only connections between the movable contact structures and their operating mechanism are the rods I54 which are of insulation; the upper end of each rod I 54 is received by a coupling member I55 pivotally connected to the movable frame I03 for the movable contact structure of one pole of the circuit breaker and the lower end of each rod I54 is received by a coupling member I56 pivotally connected to an operating arm I51 (Fig. 4). All of the operating arms I51 are secured to shaft I58 supported intermediate its ends by a pairof split bearings, not shown, one

on each of the side-plates I62.

I62 which serve as sides of the coil housing and as bearing plates for shafts of the operating mechanism, and. also provide feet upon which the vof the toggle links I15, |;.16. .toggle link I16 is pivotallyconnected bypin I11 endof core I69 is provided with an elongated slot |=13 which slidably receivesthepivot pin I14 The upper end of to that one of the arms I51 which is attached to the central-portion of shaft I58 between the plates I62 which support most of the circuit- .breaker operating mechanism. The lower end of toggle link I15 is pivotallyconnected by pin I18 to a bell-crank lever I19 whose pivot pin I provides a fixed axis for angular movement of lever I19. The ends of ,pin ISO aresuppQrtedby plates I62.

The arm I8| of lever I19 is engageable near its free end by the latchingmember I82secured to shaft I83 and biased to its-latchinglposition. When the coil of a tripping magnet, not shown, is sufficiently energized, as upon occurrence of an overload, the movement of its armature rocks shaft I83 in counterclockwise direction to release the latch I82, whereupon powerful springs,;not shown, rock the shaft I58 to open the circuit breaker.

All of the stresses incident to opening and closure of the circuit breaker are confined to the frame 5| and are not transmitted from one operating part to another through the truck frame. Moreover, since the operatingmechanism in its entirety is part of the circuit-breakerunit, it may readily be assembled ,and tested as a completely operative unit prior to mounting in the truck. Preferably the kinetic energy of the mov ing operating parts is absorbed by a friction brake B similar to that disclosed and claimed in co-pending application Serial No. 98,562.

The circuit breaker may be tripped manually by depressing the forward or handle end of lever I99 which is pivotally mounted within a housing or bracket I9I secured to the front end of the frame 5|. The handle of lever I99, as shown in Figs. 1 and 4, projects through a slot |a in the door 44 of the truck. When the handle is depressed the extension I92 of lever I99 engages the extension I93 of latch I82 to effect its release from arm |8I and so permit springs I89 to open the circuit breaker.

The circuit breaker may be reclosed manually by inserting a bar I94 through an opening I95 (Fig. 1) in the truck door and into the slot I96 of a disk I91 loosely mounted, between the sides of bracket I9I, on the shaft I98. A link, not shown, connects the disk I91 to the toggle pin I14. After the bar I94 is so inserted, it is swung downwardly through an arcof about 90 degrees and so moves pin I14 to the left; thus to rock the shaft I58 in clockwise direction to lift the rods I54 and so effect circuit-closing movement of the movable contacts of the circuit breaker. If an overload exists, the circuit-breaker cannot be held closed by bar I94 becausewhen the latch I82 is released, the togglecollapses and aforesaid powerful springs are free to open the circuit breaker regardless of the position of disk I91. The construction and operation of the operating mechanism is similar to that disclosed and claimed in Reissue Patent No. 19,753 toH. C. Graves.

Preferably, the edge of disk I91, which is visible through opening I93 in the truck door 44 is colored or otherwise marked to indicate whether the circuit b eaker is in open or closed circuit position. The disk |91 is biased to-the in bearings frame 5|.

Lmounted upon the panel 2M suitably mounted in the lower compartment of the truck. These :switches may be used to operate signal lights or perform other control functions in accordance with the position of the circuit breaker.

From the tripping lever I90 is suspended the rod 20! which extends through the base of the .truck in line with the cam 3| on the base 30 of the switchboard to trip the circuit breaker, if it be closed, as the truck is pushed into the switchboard to effect engagement of movable disconnect contacts H with the stationary disconnect contacts l2.

Each truck unit Bl-BG is locked in its innermost or normal position by a pair of racking bars 205 (Fig. 4) each having a hooked end which drops over and engages the pin 206 of one of the pair of abutment members 28 attached to the front face of each of the switchboard units SIS6; the rear face of the hooked end is suitably sloped so that if it is down when the truck is pushed into the switchboard the engagement of the sloping end with pin 206 causes the bar to lift and drop over the pin. The other end of each bar 265 is pivotally connected to a crank arm secured to shaft I98 to which is secured a notched disk accessible through the opening I95 in the door Ml of the truck. The ends of this shaft are supported IQSa in brackets integral with The actuation of the notched disk to move the :truck from its service position, in which the disconnect controls ll connect the circuit-breaker L .to the bosses 9, 9a, 9b, to a test position in which ;said disconnect connects I! are out of engagement with the stationary disconnect contacts 12, and from the test position to a wholly with drawn position is fully described in my aforer said co-pending application Serial No. 227,089. Other features of the disclosure not herein claimed are described and claimed in copending divisional application Serial No. 251,500 filed J anuary 18, 1939, Serial No. 331,507 filed April 25,

What I claim is:

l. The combination with a bus conductor, of an insulated housing extending transversely of and embracing a section of said conductor, and disconnect contact structure directly and detachably attached to and supported by said conductor within the housing and comprising structure determining the position of said housing with respect to said conductor and said contact structure.

2. The combination with a bus conductor, of a panel adjacent said conductor having a slot in alignment therewith, an insulated housing for embracing a section of said conductor and having an open end, and disconnect contact structure directly mounted on and supported solely by said conductor within said housing and comprising structure enforcing location of said housing with its open end presented to said slot.

3. A switchboard arrangement comprising the combination with a bus conductor, of an insulating housing, through ends of which said conductor extends, supported from said conductor and comprising separable parts assembled and disassembled about the conductor without dislocation thereof, insulation covering said conductor except for a short section exposed within said housing, and disconnect contact structure directly attached to said short section of exposed conductor within said housing and accessible by disassembly thereof.

4. A switchboard comprising a compartment, a plurality of bus conductors within said compartment, a plurality of individual insulated housings spaced from one another Within said compartment and each comprising separable parts assembled about and supported by a short intermediate section of one of said conductors, insulation covering each of said conductors except within said housings, and a plurality of disconnect contact structures each directly attached to one of said conductors within its associated housing accessible by disassembly thereof, and comp-rising structure coacting with said associated housing to determine the position thereof with respect to the other of said housings in said compartment.

5. A switchboard having a compartment accessible from one side of the switchboard, a panel for preventing access to said compartment from the other side of said switchboard and having a plurality of slots, a plurality of bus conductors within said compartment, a plurality of insulated housings spaced from one another within said compartment and each embracing a short intermediate section of one of said conductors, insulation covering the conductors ex cept Within said housings, and a plurality of disconnect contact structures each directly attached to and supported by one of said conductors Within its associated housing and comprising structure enforcing location of its associated housing with open end thereof presented to one of said slots.

6. A switchboard having a compartment, a plurality of bus conductors extending parallel to each other transversely of said compartment, a plurality of insulated housings staggered with respect to each other and each embracing a section of one of said conductors, disconnect contact structures each directly attached to one of said conductors within the associated housing, insulation covering each of said conductors except within said housings, and insulating panels each supporting said bus conductors and dividing said compartment into sub-compartments each containing not more than one of said housings.

'7. A switchboard comprising a normally closed compartment accessible from one side of the switchboard and having slots in a panel comprising the opposite side of the switchboard, a plurality of conductors within said compartment, a plurality of insulated housings spaced from one another within said compartment each embracing a short intermediate section of one of said conductors and having its open end presented to one of said slots, insulation covering conductors except Within said housings, and disconnect contact structures each directly attached to and supported by one of said conductors within the associated housing, and means for preventing accidental engagement with the disconnect contacts comprising movable structures mounted at the open ends of the housings and biased to block said slots.

8. The combination with spaced supporting structures of insulation, bus conductors each extending through and supported by said spaced supporting structures, and disconnect contact structures, each supported directly by and electrically connected to one of said bus conductors and separated from another of the disconnect contact structures by one of said spaced supporting structures.

9. The combination with spaced supporting structures of insulation, bus conductors each extending through and supported by said spaced supporting structures, disconnect contact structures, each supported directly by and electrically connected to one of said bus conductors, insulation covering each of said conductors except where connected to its said disconnect contact structure, and insulated housings each supported by one of said bus conductors to enclose its disconnect contact structure and separated from another of said housings by one of said spaced supporting structures.

10. A switchboard comprising bus conductors supported within a compartment, a panel for said compartment, disconnect contact structures each directly attached to and supported by one of said conductors, housings each supported by one of said conductors to enclose aforesaid disconnect contact structure mounted thereon and located by said contact structure with an open end presented to a slot in said panel, and shutter structure for each of said housings biased to close the open end thereof.

11. A switchboard having a compartment, a plurality of bus conductors extending substantially parallel to each other transversely of said compartment, a plurality of housings of insulating material staggered with respect to each other and each embracing a relatively short portion of one of said bus conductors, disconnect contact means comprising electrically conductive structures each attached to a different one of said bus conductors within its associated one of said housings, insulation for each of said bus conductors complementary to its insulation afforded by its associated housing in completion of electrical isolation Within said compartment of each of said bus conductors, and insulating panels each supporting said bus conductors and jointly dividing said compartment into sub-compartments each containing not more than one of said housings.

WILLIAM M. SCOTT, JR. 

